Abstract: Programmable control devices that rely on time-of-day accuracy maintain that accuracy by determining their location via a global positioning system, recording and timestamping continually measured ambient light via a daylight sensor and real-time clock (RTC) of the programmable control device, determining a mid-darkness time point, comparing that mid-darkness time point with a reference mid-darkness time point for the same location for the same day of the year, and then adjusting the RTC of the programmable control device as necessary. Methods of maintaining time of day in a programmable control device are also provided, as are other aspects.

Abstract: A method of storing sand coated with calcium chloride is disclosed which method comprises covering the sand with a plastic sheet which is then coated with a layer of plastic foam to protect the sand from moisture and to keep the cover in place.